In flat panel display devices, the thin film transistor liquid crystal display (TFT-LCD) has the advantages of small volume, low energy consumption, relatively low manufacturing cost, and low radiation, etc., thus takes the leading role in the current flat panel display market. Currently, the display modes for TFT-LCD are primarily the twisted nematic (TN) mode, vertical alignment (VA) mode, in-plane switching (IPS) mode, and advanced super dimension switch (AD-SDS or ADS) mode, etc.
An ADS mode based display forms a multi-dimensional electric field by the electric field generated at the edge of the common electrode within the same plane and the electric field generated between the common electrode layer and the plate electrode layer, enabling liquid crystal molecules of all orientations right above the common electrodes and between the common electrodes within the liquid crystal cell, so as to improve the working efficiency of the liquid crystal and increase the transmissive efficiency. The advanced super dimension switch technique can improve the graphic quality of TFT-LCD, enabling advantages such as high definition, high transmissivity, low energy consumption, wide visual angle, high aperture ration, low color difference, no push Mura, and the like.
Based on differences in the molecular arrangement, liquid crystals can be divided into nematic liquid crystals, smectic liquid crystals, and cholesteric liquid crystals, and the like. Currently, nematic liquid crystals are widely used in TFT-LCD, whereas use of other kinds of liquid crystals is limited. Nematic liquid crystals can be divided into positive nematic liquid crystals, negative nematic liquid crystals, and dual frequency liquid crystals. Where an electrophilic group is at the end of the long axis of a rod-like liquid crystal molecule, the dielectric constant of the liquid crystal (Δ∈) is larger than zero, and the liquid crystal is positive. Where an electrophilic group is at the end of the short axis of a rod-like liquid crystal molecule, Δ∈ is smaller than zero, and the liquid crystal is negative. Positive nematic liquid crystals are primarily used for display modes such as TN, ADS, IPS, and the like. Negative nematic liquid crystals are primarily used for modes such as VA and the like. For dual frequency liquid crystals, where it is under the action of the low frequency electric field, Δ∈ is larger than zero, and the liquid crystal exhibits a positive dielectricity. Where it is under the action of the high frequency electric field, Δ∈ is smaller than zero, and the liquid crystal exhibits a negative dielectricity. Because the dual frequency liquid crystal exhibits different electricity with the change of the electric field frequency, it may cause abnormality in the arrangement of the dual frequency liquid crystal molecules, and therefore it is difficult for applying to the liquid crystal display.